1. Field of the Invention
The present invention relates to an optical recording/reproducing apparatus which records or reproduces information on or from an information recording medium such as an optical disk, and particularly relates to adjustment of a laser power during recording.
2. Description of the Related Art
An optical recording/reproducing apparatus is mainly used as a peripheral device of a personal computer or the like, and has been developed as high-capacity data storage equipment due to easy-portability and a low price of the medium. In particular, the optical recording/reproducing apparatus has such data accessibility advantageousness as to be capable of intermittently recording a continuous data and reproducing an arbitrary part of the continuous data at a high speed at random, which cannot be realized by a tape-shaped recording medium.
Now, the optical recording/reproducing apparatus further progresses so as to cope with the tendency of higher density and increase the speed of the transfer rate, and has an open application field in a digital recording/reproducing apparatus with high-definition image information, as leading multi-media equipment.
Thus, in the optical recording/reproducing apparatus having attained high speed and high density, it is very important to optimally adjust a recording power of a laser beam in the record or reproduction of the data. The optimum recording power is affected by a track width, a pitch, a groove shape, the sensitivity of a material of a dye layer, the uniformity of the dye layer in a radius direction and the like in an optical disk (medium).
Generally, such an individual difference among disks is specific to each optical disk, and the optimum recording power changes depending on the optical disk. Even in the same optical disk, the optimum recording power changes along with time, being caused by a warp of an optical disk, a dirt on an optical disk and an increase in the usage count, and depending on how an optical disk is kept. Thus, the effective value of the recording power changes, and then the optimum value of the recording power varies. In a process of recording/reproducing these optical disks, the optimum recording power or the optimum reproduction power may change due to the change of temperature in the apparatus, depending on a use environment.
For this reason, Japanese Patent Application Laid-Open No. H07-244930 proposes a technique of reproducing a region which has recorded immediately before, during a pausing period in intermittent recording, and correcting the recording power in accordance with the obtained reproduced signal, as a method of correcting the recording power in accordance with a difference of characteristics in a radius direction of the optical disk and the temperature change during recording.
However, when the technique is used in a recording device such as a DVD recorder or a video camcorder, a recording standby period is occasionally prolonged by the pause operation. Then, the temperature can largely change in the recording standby period. The conventional method described in the above described patent document sets the recording power at the optimum recording power for the temperature at previous recording, so that the optimum recording power results in being different from the previously set optimum recording power, when the temperature largely changes before the recording apparatus restarts recording.